(unstack b5 b3)
(putdown b5)
(unstack b3 b4)
(stack b3 b5)
(unstack b4 b2)
(stack b4 b3)
(unstack b2 b1)
(putdown b2)
(pickup b1)
(stack b1 b2)
(unstack b4 b3)
(stack b4 b1)
; cost = 12 (unit cost)
